Pitch‐intensity effects and model calculation of the level dependence of VIIIth nerve response functions

Abstract

It has been suggested that pitch intensity effects may be correlated with level‐dependent shifts in the location of peaks in the VIIIth nerve interspike interval (ISI) histogram [K. Jones, A. Tubis, and E. M. Burns, J. Acoust. Soc. Am. Suppl. 1 74, S8 (1983)]. In order to further explore this possibility, we have carried out a detailed numerical simulation of these shifts and compared them with average human pitch‐intensity data. We use the conventional stochastic neural firing model in which the conditional probability for a firing in the brief time interval (t, t + Δt) subsequent to the last previous firing at time t′ is s(t)r(t − t′)Δt, where s(t) is the signal‐excitation function and r(t − t′) is the neural refractory function. We use the empirical PST response function of D. H. Johnson [Ph.D. thesis, MIT (1974)], the neural refractory function of R. P. Gaumond [Ph.D. thesis, Washington University (1980)], and the technique of K. Jones, A. Tubis, and E. M. Burns [J. Acoust. Soc. Am. 78, 90–94 (1985)] for extracting s(t) from the PST response. [Work supported by NIH.]